Summary At about 1500 eastern standard time, the pilot of an Aerospatiale AS350BA helicopter, registration C-FHBG, serial number1440, with four hunters and one guide on board, was on approach to an unprepared landing area at the edge of a lake in the James Bay region 60nautical miles from LaGrande-4, Quebec. On completing the approach, the helicopter commenced hovering, then started to descend in white-out and powdery snow conditions. The snow picked up by the rotor wash caused a total loss of visual references. After the left skid touched the snow-covered surface, the helicopter rolled left in the snow, which was several feet deep at the time. As it rolled, the rotor blades struck the ground and the transmission separated partially from its mounts. Blades entered the cockpit and fatally injured the guide and pilot, who was wearing a helmet. The four passengers in the rear seats were not wearing seat-belts, and they suffered minor injuries. Two of them were thrown about 10feet from the wreck, and the other two remained in the cabin. The survivors were evacuated around 1630 by two other helicopters. Ce rapport est galement disponible en franais. Other Factual Information The AS-350 BA had been chartered by Mirage outfitters to transport and move its clients around the hunting area near the Sakami River some 45nm south of the main camp (see AppendixA). The outfitters had prepared an airstrip on the river, where its clients gathered before being flown to the area near the caribou herds. Four hunters and a guide made up one party. On the day of the accident, the helicopter had made five flights before landing on the Sakami River around 14301 to pick up its third hunting party. The pilot left the engine running. The guide assigned to the aircraft disembarked and helped the four hunters to board. He then took the left front seat and fastened his seat-belt. The aircraft took off and, around 1500, after a brief flight, it made an approach for a landing on the frozen surface of a lake (5302'50"N, 07229'30"W). When the aircraft touched the surface, it rolled over on its left side. After the crash, a passenger called for rescue on a satellite telephone he found in the cabin; the telephone belonged to Hli-Horizon. The survivors were rescued around 1630by two helicopters chartered by Mirage outfitters to fly hunters to the same hunting area. The pilot was trained, certified and qualified for the flight in accordance with existing regulations. He had been flying as a commercial helicopter pilot since1996. The weather on the day of the accident was conducive to white-out; the sky was uniformly overcast. In these conditions, there were no shadows, causing a loss of depth perception. It had snowed the day before and the ground was covered with a layer of powdery snow. The exterior temperature was hovering around -20C. Last light was at1701. The pilot had not reported any faults before the flight. The helicopter had flown 25hours since its last 100-hour inspection. The aircraft was inspected and maintained in accordance with a maintenance program approved by Transport Canada. The aircraft documentation revealed no deferred maintenance items. At the time of the accident, the windows in the front and rear doors were completely iced up and the left windshield was partially iced up, but the pilot's windshield was defrosted. It was not determined whether or not the two floor windows were iced up. The accident occurred at the edge of a wood and beside a lake, on terrain that was sloped about 20degrees (Photo1). After the accident, the helicopter was lying on its left side with the rotor mast pointing up the slope. The cockpit roof had been torn off. There were blade impact marks on the forward portion of the headliner, the pillar between the windshields and the front door frames. All damages were attributed to instantaneous overload. The transmission was torn away, and the main rotor blades and rotor hub exhibited damages consistent with the aircraft rolling onto its side. Photo 1 - Aircraft wreckage andaccident site The guide's and pilot's seats separated from their anchors when the helicopter rolled over. Examination of the seats revealed that the rails of both seats were deformed under lateral loading. In 1999,Eurocopter issued service bulletin25.00.63, recommending that the seat anchors be reinforced in case of a hard landing. The recommended modification was not made on the accident aircraft. Actioning service bulletins is optional. In powdery snow conditions, two landing techniques are recommended as a means of preventing a loss of visual references due to snow being picked up by rotor wash. Over open ground, a landing with no hover phase is recommended. For landings in a confined space, the pilot should hover higher than usual, select specific reference points, and descend very slowly. He can then land when all powdery snow has been blown away by rotor wash. On a landing on sloping terrain, rotor lift can generate roll and cause the helicopter to roll over on its side. This effect is called "dynamic rollover." Each helicopter has its own critical roll angle, beyond which recovery is impossible. If that critical angle is exceeded, the helicopter will roll even if maximum opposing cyclic input is applied. In fact, the critical angle is equivalent to full cyclic deflection. When only one skid of the helicopter is in contact with the ground, sideways movement can cause a high rate of roll and a roll angle that exceeds the critical angle dictated by the maximum lateral deflection of the cyclic control. Section 602.89 of the Canadian Aviation Regulations (CARs) requires that pilots ensure that all passengers on board are briefed before take-off on: the location and means of operation of safety belts; the stowage of carry-on baggage; the location and means of operation of emergency and normal exits; and the location of first-aid kits and the use of survival equipment and the emergency locator transmitter (ELT). The four hunters in the rear seats were not given the necessary safety instructions prior to departure. Moreover, none of them had their seat-belt fastened; the pilot did not ensure they had done so before take-off. The passengers were not very familiar with the aircraft and did not know there was survival equipment on board. The same was true of the fixed-wing flight earlier that morning that brought the hunters to the Sakami River airstrip, as well as the helicopter flight when they were rescued after the accident. The investigation further established that the two hunting parties that had been flown in earlier on the same helicopter had not been given a safety briefing prior to take-off. The aircraft was carrying the survival equipment required for the flight under CARs. It was carrying the Survie Max model survival gear approved for six persons for a period of five days, which was manufactured by Survie Saguenay. It also carried a model 300S emergency tent designed for six persons and manufactured by Camshell. The survival gear was in the left baggage compartment. Since the aircraft was lying on its left side after the accident, the survival gear was not accessible at that time. The helicopter was equipped with a Pointer Sentry model 4000-10ELT, which activated on impact. It was mounted in accordance with existing regulations in the forward part of the cabin below the instrument panel, and its selector switch was in the correct position for automatic activation. The ELT signal was received by the search and rescue satellite (SARSAT) network 48minutes after the accident.